A little background: We were friends for two years then we started dating and she got pregnant. I was estatic, she wasn't. Her mother and grandmother tried to talk her into an abortion but she didn't, though she thought about it. We had our son and now all of them are superficially happy about a child 6 months before they didn't want.

Problem: Me and my girlfriend set up an unwritten contract of how we'd care for the child. But since he's been born she acts like [b]"Our"[/b] son is just [b]"her"[/b] son. I confronted her about it and she refused to answer (opting to hang up in my face).

Question: Should I try to work it out for my son's sake or leave this stressing relationship (while remaining in my son's life)?

Try and sort it out
My mum and dad split on christmas day when I was twelve, Im telling you this from the childs point of view, not a perents. Try your absolute hardest to have everything you deserve with him. My dad didnt, I dont even think he knows how old I am.
It's not fair to leave it, and kids -even at six months- can detect emotions. A stressful environment will make a stressful child

If you really think that you will be able to remain in your son's life if you leave the "stressful situation" with his mother behind I think that is the best. Another story coming from a child of divorced parents. I couldn't stand my father when my parents were together, in fact because of all the fighting and the tension that was between them I didn't want much to do with either of them. But shortly after they got divorced (this was when I was in 5th grade) things began to mellow out, my relationship with my father actually began to grow, until he was something close to my best friend, as much as a parent could be anyway. My parents tried to stay together for my sake, and it just made my life miserable, and probably theirs too. Even though your son is still young he'll be able to pick up on the mood between you two.

Its something to keep in mind, but of course everyone's situation is different in the end just do what you think is right.